Commit | Line | Data |
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8ae12a0d DB |
1 | /* |
2 | * spi.c - SPI init/core code | |
3 | * | |
4 | * Copyright (C) 2005 David Brownell | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | ||
8ae12a0d DB |
21 | #include <linux/kernel.h> |
22 | #include <linux/device.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/cache.h> | |
94040828 | 25 | #include <linux/mutex.h> |
8ae12a0d DB |
26 | #include <linux/spi/spi.h> |
27 | ||
28 | ||
b885244e DB |
29 | /* SPI bustype and spi_master class are registered after board init code |
30 | * provides the SPI device tables, ensuring that both are present by the | |
31 | * time controller driver registration causes spi_devices to "enumerate". | |
8ae12a0d DB |
32 | */ |
33 | static void spidev_release(struct device *dev) | |
34 | { | |
0ffa0285 | 35 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
36 | |
37 | /* spi masters may cleanup for released devices */ | |
38 | if (spi->master->cleanup) | |
39 | spi->master->cleanup(spi); | |
40 | ||
0c868461 | 41 | spi_master_put(spi->master); |
8ae12a0d DB |
42 | kfree(dev); |
43 | } | |
44 | ||
45 | static ssize_t | |
46 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
47 | { | |
48 | const struct spi_device *spi = to_spi_device(dev); | |
49 | ||
50 | return snprintf(buf, BUS_ID_SIZE + 1, "%s\n", spi->modalias); | |
51 | } | |
52 | ||
53 | static struct device_attribute spi_dev_attrs[] = { | |
54 | __ATTR_RO(modalias), | |
55 | __ATTR_NULL, | |
56 | }; | |
57 | ||
58 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
59 | * and the sysfs version makes coldplug work too. | |
60 | */ | |
61 | ||
62 | static int spi_match_device(struct device *dev, struct device_driver *drv) | |
63 | { | |
64 | const struct spi_device *spi = to_spi_device(dev); | |
65 | ||
66 | return strncmp(spi->modalias, drv->name, BUS_ID_SIZE) == 0; | |
67 | } | |
68 | ||
7eff2e7a | 69 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
70 | { |
71 | const struct spi_device *spi = to_spi_device(dev); | |
72 | ||
7eff2e7a | 73 | add_uevent_var(env, "MODALIAS=%s", spi->modalias); |
8ae12a0d DB |
74 | return 0; |
75 | } | |
76 | ||
77 | #ifdef CONFIG_PM | |
78 | ||
8ae12a0d DB |
79 | static int spi_suspend(struct device *dev, pm_message_t message) |
80 | { | |
3c72426f | 81 | int value = 0; |
b885244e | 82 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 83 | |
8ae12a0d | 84 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
85 | if (drv) { |
86 | if (drv->suspend) | |
87 | value = drv->suspend(to_spi_device(dev), message); | |
88 | else | |
89 | dev_dbg(dev, "... can't suspend\n"); | |
90 | } | |
8ae12a0d DB |
91 | return value; |
92 | } | |
93 | ||
94 | static int spi_resume(struct device *dev) | |
95 | { | |
3c72426f | 96 | int value = 0; |
b885244e | 97 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 98 | |
8ae12a0d | 99 | /* resume may restart the i/o queue */ |
3c72426f DB |
100 | if (drv) { |
101 | if (drv->resume) | |
102 | value = drv->resume(to_spi_device(dev)); | |
103 | else | |
104 | dev_dbg(dev, "... can't resume\n"); | |
105 | } | |
8ae12a0d DB |
106 | return value; |
107 | } | |
108 | ||
109 | #else | |
110 | #define spi_suspend NULL | |
111 | #define spi_resume NULL | |
112 | #endif | |
113 | ||
114 | struct bus_type spi_bus_type = { | |
115 | .name = "spi", | |
116 | .dev_attrs = spi_dev_attrs, | |
117 | .match = spi_match_device, | |
118 | .uevent = spi_uevent, | |
119 | .suspend = spi_suspend, | |
120 | .resume = spi_resume, | |
121 | }; | |
122 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
123 | ||
b885244e DB |
124 | |
125 | static int spi_drv_probe(struct device *dev) | |
126 | { | |
127 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
128 | ||
129 | return sdrv->probe(to_spi_device(dev)); | |
130 | } | |
131 | ||
132 | static int spi_drv_remove(struct device *dev) | |
133 | { | |
134 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
135 | ||
136 | return sdrv->remove(to_spi_device(dev)); | |
137 | } | |
138 | ||
139 | static void spi_drv_shutdown(struct device *dev) | |
140 | { | |
141 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
142 | ||
143 | sdrv->shutdown(to_spi_device(dev)); | |
144 | } | |
145 | ||
33e34dc6 DB |
146 | /** |
147 | * spi_register_driver - register a SPI driver | |
148 | * @sdrv: the driver to register | |
149 | * Context: can sleep | |
150 | */ | |
b885244e DB |
151 | int spi_register_driver(struct spi_driver *sdrv) |
152 | { | |
153 | sdrv->driver.bus = &spi_bus_type; | |
154 | if (sdrv->probe) | |
155 | sdrv->driver.probe = spi_drv_probe; | |
156 | if (sdrv->remove) | |
157 | sdrv->driver.remove = spi_drv_remove; | |
158 | if (sdrv->shutdown) | |
159 | sdrv->driver.shutdown = spi_drv_shutdown; | |
160 | return driver_register(&sdrv->driver); | |
161 | } | |
162 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
163 | ||
8ae12a0d DB |
164 | /*-------------------------------------------------------------------------*/ |
165 | ||
166 | /* SPI devices should normally not be created by SPI device drivers; that | |
167 | * would make them board-specific. Similarly with SPI master drivers. | |
168 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
169 | * with other readonly (flashable) information about mainboard devices. | |
170 | */ | |
171 | ||
172 | struct boardinfo { | |
173 | struct list_head list; | |
174 | unsigned n_board_info; | |
175 | struct spi_board_info board_info[0]; | |
176 | }; | |
177 | ||
178 | static LIST_HEAD(board_list); | |
94040828 | 179 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 180 | |
dc87c98e GL |
181 | /** |
182 | * spi_alloc_device - Allocate a new SPI device | |
183 | * @master: Controller to which device is connected | |
184 | * Context: can sleep | |
185 | * | |
186 | * Allows a driver to allocate and initialize a spi_device without | |
187 | * registering it immediately. This allows a driver to directly | |
188 | * fill the spi_device with device parameters before calling | |
189 | * spi_add_device() on it. | |
190 | * | |
191 | * Caller is responsible to call spi_add_device() on the returned | |
192 | * spi_device structure to add it to the SPI master. If the caller | |
193 | * needs to discard the spi_device without adding it, then it should | |
194 | * call spi_dev_put() on it. | |
195 | * | |
196 | * Returns a pointer to the new device, or NULL. | |
197 | */ | |
198 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
199 | { | |
200 | struct spi_device *spi; | |
201 | struct device *dev = master->dev.parent; | |
202 | ||
203 | if (!spi_master_get(master)) | |
204 | return NULL; | |
205 | ||
206 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
207 | if (!spi) { | |
208 | dev_err(dev, "cannot alloc spi_device\n"); | |
209 | spi_master_put(master); | |
210 | return NULL; | |
211 | } | |
212 | ||
213 | spi->master = master; | |
214 | spi->dev.parent = dev; | |
215 | spi->dev.bus = &spi_bus_type; | |
216 | spi->dev.release = spidev_release; | |
217 | device_initialize(&spi->dev); | |
218 | return spi; | |
219 | } | |
220 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
221 | ||
222 | /** | |
223 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
224 | * @spi: spi_device to register | |
225 | * | |
226 | * Companion function to spi_alloc_device. Devices allocated with | |
227 | * spi_alloc_device can be added onto the spi bus with this function. | |
228 | * | |
e48880e0 | 229 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
230 | */ |
231 | int spi_add_device(struct spi_device *spi) | |
232 | { | |
e48880e0 | 233 | static DEFINE_MUTEX(spi_add_lock); |
dc87c98e GL |
234 | struct device *dev = spi->master->dev.parent; |
235 | int status; | |
236 | ||
237 | /* Chipselects are numbered 0..max; validate. */ | |
238 | if (spi->chip_select >= spi->master->num_chipselect) { | |
239 | dev_err(dev, "cs%d >= max %d\n", | |
240 | spi->chip_select, | |
241 | spi->master->num_chipselect); | |
242 | return -EINVAL; | |
243 | } | |
244 | ||
245 | /* Set the bus ID string */ | |
246 | snprintf(spi->dev.bus_id, sizeof spi->dev.bus_id, | |
247 | "%s.%u", spi->master->dev.bus_id, | |
248 | spi->chip_select); | |
249 | ||
e48880e0 DB |
250 | |
251 | /* We need to make sure there's no other device with this | |
252 | * chipselect **BEFORE** we call setup(), else we'll trash | |
253 | * its configuration. Lock against concurrent add() calls. | |
254 | */ | |
255 | mutex_lock(&spi_add_lock); | |
256 | ||
257 | if (bus_find_device_by_name(&spi_bus_type, NULL, spi->dev.bus_id) | |
258 | != NULL) { | |
259 | dev_err(dev, "chipselect %d already in use\n", | |
260 | spi->chip_select); | |
261 | status = -EBUSY; | |
262 | goto done; | |
263 | } | |
264 | ||
265 | /* Drivers may modify this initial i/o setup, but will | |
266 | * normally rely on the device being setup. Devices | |
267 | * using SPI_CS_HIGH can't coexist well otherwise... | |
268 | */ | |
dc87c98e GL |
269 | status = spi->master->setup(spi); |
270 | if (status < 0) { | |
271 | dev_err(dev, "can't %s %s, status %d\n", | |
272 | "setup", spi->dev.bus_id, status); | |
e48880e0 | 273 | goto done; |
dc87c98e GL |
274 | } |
275 | ||
e48880e0 | 276 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 277 | status = device_add(&spi->dev); |
e48880e0 | 278 | if (status < 0) |
dc87c98e GL |
279 | dev_err(dev, "can't %s %s, status %d\n", |
280 | "add", spi->dev.bus_id, status); | |
e48880e0 DB |
281 | else |
282 | dev_dbg(dev, "registered child %s\n", spi->dev.bus_id); | |
dc87c98e | 283 | |
e48880e0 DB |
284 | done: |
285 | mutex_unlock(&spi_add_lock); | |
286 | return status; | |
dc87c98e GL |
287 | } |
288 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 289 | |
33e34dc6 DB |
290 | /** |
291 | * spi_new_device - instantiate one new SPI device | |
292 | * @master: Controller to which device is connected | |
293 | * @chip: Describes the SPI device | |
294 | * Context: can sleep | |
295 | * | |
296 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
297 | * after board init creates the hard-wired devices. Some development |
298 | * platforms may not be able to use spi_register_board_info though, and | |
299 | * this is exported so that for example a USB or parport based adapter | |
300 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
301 | * |
302 | * Returns the new device, or NULL. | |
8ae12a0d | 303 | */ |
e9d5a461 AB |
304 | struct spi_device *spi_new_device(struct spi_master *master, |
305 | struct spi_board_info *chip) | |
8ae12a0d DB |
306 | { |
307 | struct spi_device *proxy; | |
8ae12a0d DB |
308 | int status; |
309 | ||
082c8cb4 DB |
310 | /* NOTE: caller did any chip->bus_num checks necessary. |
311 | * | |
312 | * Also, unless we change the return value convention to use | |
313 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
314 | * suggests syslogged diagnostics are best here (ugh). | |
315 | */ | |
316 | ||
dc87c98e GL |
317 | proxy = spi_alloc_device(master); |
318 | if (!proxy) | |
8ae12a0d DB |
319 | return NULL; |
320 | ||
102eb975 GL |
321 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
322 | ||
8ae12a0d DB |
323 | proxy->chip_select = chip->chip_select; |
324 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 325 | proxy->mode = chip->mode; |
8ae12a0d | 326 | proxy->irq = chip->irq; |
102eb975 | 327 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
328 | proxy->dev.platform_data = (void *) chip->platform_data; |
329 | proxy->controller_data = chip->controller_data; | |
330 | proxy->controller_state = NULL; | |
8ae12a0d | 331 | |
dc87c98e | 332 | status = spi_add_device(proxy); |
8ae12a0d | 333 | if (status < 0) { |
dc87c98e GL |
334 | spi_dev_put(proxy); |
335 | return NULL; | |
8ae12a0d DB |
336 | } |
337 | ||
8ae12a0d DB |
338 | return proxy; |
339 | } | |
340 | EXPORT_SYMBOL_GPL(spi_new_device); | |
341 | ||
33e34dc6 DB |
342 | /** |
343 | * spi_register_board_info - register SPI devices for a given board | |
344 | * @info: array of chip descriptors | |
345 | * @n: how many descriptors are provided | |
346 | * Context: can sleep | |
347 | * | |
8ae12a0d DB |
348 | * Board-specific early init code calls this (probably during arch_initcall) |
349 | * with segments of the SPI device table. Any device nodes are created later, | |
350 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
351 | * this table of devices forever, so that reloading a controller driver will | |
352 | * not make Linux forget about these hard-wired devices. | |
353 | * | |
354 | * Other code can also call this, e.g. a particular add-on board might provide | |
355 | * SPI devices through its expansion connector, so code initializing that board | |
356 | * would naturally declare its SPI devices. | |
357 | * | |
358 | * The board info passed can safely be __initdata ... but be careful of | |
359 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
360 | */ | |
361 | int __init | |
362 | spi_register_board_info(struct spi_board_info const *info, unsigned n) | |
363 | { | |
364 | struct boardinfo *bi; | |
365 | ||
b885244e | 366 | bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL); |
8ae12a0d DB |
367 | if (!bi) |
368 | return -ENOMEM; | |
369 | bi->n_board_info = n; | |
b885244e | 370 | memcpy(bi->board_info, info, n * sizeof *info); |
8ae12a0d | 371 | |
94040828 | 372 | mutex_lock(&board_lock); |
8ae12a0d | 373 | list_add_tail(&bi->list, &board_list); |
94040828 | 374 | mutex_unlock(&board_lock); |
8ae12a0d DB |
375 | return 0; |
376 | } | |
8ae12a0d DB |
377 | |
378 | /* FIXME someone should add support for a __setup("spi", ...) that | |
379 | * creates board info from kernel command lines | |
380 | */ | |
381 | ||
149a6501 | 382 | static void scan_boardinfo(struct spi_master *master) |
8ae12a0d DB |
383 | { |
384 | struct boardinfo *bi; | |
8ae12a0d | 385 | |
94040828 | 386 | mutex_lock(&board_lock); |
8ae12a0d DB |
387 | list_for_each_entry(bi, &board_list, list) { |
388 | struct spi_board_info *chip = bi->board_info; | |
389 | unsigned n; | |
390 | ||
391 | for (n = bi->n_board_info; n > 0; n--, chip++) { | |
392 | if (chip->bus_num != master->bus_num) | |
393 | continue; | |
082c8cb4 DB |
394 | /* NOTE: this relies on spi_new_device to |
395 | * issue diagnostics when given bogus inputs | |
8ae12a0d | 396 | */ |
8ae12a0d DB |
397 | (void) spi_new_device(master, chip); |
398 | } | |
399 | } | |
94040828 | 400 | mutex_unlock(&board_lock); |
8ae12a0d DB |
401 | } |
402 | ||
403 | /*-------------------------------------------------------------------------*/ | |
404 | ||
49dce689 | 405 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
406 | { |
407 | struct spi_master *master; | |
408 | ||
49dce689 | 409 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
410 | kfree(master); |
411 | } | |
412 | ||
413 | static struct class spi_master_class = { | |
414 | .name = "spi_master", | |
415 | .owner = THIS_MODULE, | |
49dce689 | 416 | .dev_release = spi_master_release, |
8ae12a0d DB |
417 | }; |
418 | ||
419 | ||
420 | /** | |
421 | * spi_alloc_master - allocate SPI master controller | |
422 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 423 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 424 | * memory is in the driver_data field of the returned device, |
0c868461 | 425 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 426 | * Context: can sleep |
8ae12a0d DB |
427 | * |
428 | * This call is used only by SPI master controller drivers, which are the | |
429 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 430 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
431 | * |
432 | * This must be called from context that can sleep. It returns the SPI | |
433 | * master structure on success, else NULL. | |
434 | * | |
435 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 436 | * the master's methods before calling spi_register_master(); and (after errors |
0c868461 | 437 | * adding the device) calling spi_master_put() to prevent a memory leak. |
8ae12a0d | 438 | */ |
e9d5a461 | 439 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
440 | { |
441 | struct spi_master *master; | |
442 | ||
0c868461 DB |
443 | if (!dev) |
444 | return NULL; | |
445 | ||
e94b1766 | 446 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
447 | if (!master) |
448 | return NULL; | |
449 | ||
49dce689 TJ |
450 | device_initialize(&master->dev); |
451 | master->dev.class = &spi_master_class; | |
452 | master->dev.parent = get_device(dev); | |
0c868461 | 453 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
454 | |
455 | return master; | |
456 | } | |
457 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
458 | ||
459 | /** | |
460 | * spi_register_master - register SPI master controller | |
461 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 462 | * Context: can sleep |
8ae12a0d DB |
463 | * |
464 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
465 | * such as the platform bus. The final stage of probe() in that code | |
466 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
467 | * | |
468 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
469 | * and board-specific addressing for SPI devices combines those numbers | |
470 | * with chip select numbers. Since SPI does not directly support dynamic | |
471 | * device identification, boards need configuration tables telling which | |
472 | * chip is at which address. | |
473 | * | |
474 | * This must be called from context that can sleep. It returns zero on | |
475 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
476 | * After a successful return, the caller is responsible for calling |
477 | * spi_unregister_master(). | |
8ae12a0d | 478 | */ |
e9d5a461 | 479 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 480 | { |
e44a45ae | 481 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 482 | struct device *dev = master->dev.parent; |
8ae12a0d DB |
483 | int status = -ENODEV; |
484 | int dynamic = 0; | |
485 | ||
0c868461 DB |
486 | if (!dev) |
487 | return -ENODEV; | |
488 | ||
082c8cb4 DB |
489 | /* even if it's just one always-selected device, there must |
490 | * be at least one chipselect | |
491 | */ | |
492 | if (master->num_chipselect == 0) | |
493 | return -EINVAL; | |
494 | ||
8ae12a0d | 495 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 496 | if (master->bus_num < 0) { |
082c8cb4 DB |
497 | /* FIXME switch to an IDR based scheme, something like |
498 | * I2C now uses, so we can't run out of "dynamic" IDs | |
499 | */ | |
8ae12a0d | 500 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 501 | dynamic = 1; |
8ae12a0d DB |
502 | } |
503 | ||
504 | /* register the device, then userspace will see it. | |
505 | * registration fails if the bus ID is in use. | |
506 | */ | |
49dce689 | 507 | snprintf(master->dev.bus_id, sizeof master->dev.bus_id, |
8ae12a0d | 508 | "spi%u", master->bus_num); |
49dce689 | 509 | status = device_add(&master->dev); |
b885244e | 510 | if (status < 0) |
8ae12a0d | 511 | goto done; |
49dce689 | 512 | dev_dbg(dev, "registered master %s%s\n", master->dev.bus_id, |
8ae12a0d DB |
513 | dynamic ? " (dynamic)" : ""); |
514 | ||
515 | /* populate children from any spi device tables */ | |
516 | scan_boardinfo(master); | |
517 | status = 0; | |
518 | done: | |
519 | return status; | |
520 | } | |
521 | EXPORT_SYMBOL_GPL(spi_register_master); | |
522 | ||
523 | ||
350d0076 | 524 | static int __unregister(struct device *dev, void *master_dev) |
8ae12a0d DB |
525 | { |
526 | /* note: before about 2.6.14-rc1 this would corrupt memory: */ | |
350d0076 AN |
527 | if (dev != master_dev) |
528 | spi_unregister_device(to_spi_device(dev)); | |
8ae12a0d DB |
529 | return 0; |
530 | } | |
531 | ||
532 | /** | |
533 | * spi_unregister_master - unregister SPI master controller | |
534 | * @master: the master being unregistered | |
33e34dc6 | 535 | * Context: can sleep |
8ae12a0d DB |
536 | * |
537 | * This call is used only by SPI master controller drivers, which are the | |
538 | * only ones directly touching chip registers. | |
539 | * | |
540 | * This must be called from context that can sleep. | |
541 | */ | |
542 | void spi_unregister_master(struct spi_master *master) | |
543 | { | |
89fc9a1a JG |
544 | int dummy; |
545 | ||
350d0076 AN |
546 | dummy = device_for_each_child(master->dev.parent, &master->dev, |
547 | __unregister); | |
49dce689 | 548 | device_unregister(&master->dev); |
8ae12a0d DB |
549 | } |
550 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
551 | ||
5ed2c832 DY |
552 | static int __spi_master_match(struct device *dev, void *data) |
553 | { | |
554 | struct spi_master *m; | |
555 | u16 *bus_num = data; | |
556 | ||
557 | m = container_of(dev, struct spi_master, dev); | |
558 | return m->bus_num == *bus_num; | |
559 | } | |
560 | ||
8ae12a0d DB |
561 | /** |
562 | * spi_busnum_to_master - look up master associated with bus_num | |
563 | * @bus_num: the master's bus number | |
33e34dc6 | 564 | * Context: can sleep |
8ae12a0d DB |
565 | * |
566 | * This call may be used with devices that are registered after | |
567 | * arch init time. It returns a refcounted pointer to the relevant | |
568 | * spi_master (which the caller must release), or NULL if there is | |
569 | * no such master registered. | |
570 | */ | |
571 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
572 | { | |
49dce689 | 573 | struct device *dev; |
1e9a51dc | 574 | struct spi_master *master = NULL; |
5ed2c832 | 575 | |
695794ae | 576 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
577 | __spi_master_match); |
578 | if (dev) | |
579 | master = container_of(dev, struct spi_master, dev); | |
580 | /* reference got in class_find_device */ | |
1e9a51dc | 581 | return master; |
8ae12a0d DB |
582 | } |
583 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
584 | ||
585 | ||
586 | /*-------------------------------------------------------------------------*/ | |
587 | ||
5d870c8e AM |
588 | static void spi_complete(void *arg) |
589 | { | |
590 | complete(arg); | |
591 | } | |
592 | ||
8ae12a0d DB |
593 | /** |
594 | * spi_sync - blocking/synchronous SPI data transfers | |
595 | * @spi: device with which data will be exchanged | |
596 | * @message: describes the data transfers | |
33e34dc6 | 597 | * Context: can sleep |
8ae12a0d DB |
598 | * |
599 | * This call may only be used from a context that may sleep. The sleep | |
600 | * is non-interruptible, and has no timeout. Low-overhead controller | |
601 | * drivers may DMA directly into and out of the message buffers. | |
602 | * | |
603 | * Note that the SPI device's chip select is active during the message, | |
604 | * and then is normally disabled between messages. Drivers for some | |
605 | * frequently-used devices may want to minimize costs of selecting a chip, | |
606 | * by leaving it selected in anticipation that the next message will go | |
607 | * to the same chip. (That may increase power usage.) | |
608 | * | |
0c868461 DB |
609 | * Also, the caller is guaranteeing that the memory associated with the |
610 | * message will not be freed before this call returns. | |
611 | * | |
9b938b74 | 612 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
613 | */ |
614 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
615 | { | |
60be6b9a | 616 | DECLARE_COMPLETION_ONSTACK(done); |
8ae12a0d DB |
617 | int status; |
618 | ||
5d870c8e | 619 | message->complete = spi_complete; |
8ae12a0d DB |
620 | message->context = &done; |
621 | status = spi_async(spi, message); | |
9b938b74 | 622 | if (status == 0) { |
8ae12a0d | 623 | wait_for_completion(&done); |
9b938b74 MP |
624 | status = message->status; |
625 | } | |
8ae12a0d DB |
626 | message->context = NULL; |
627 | return status; | |
628 | } | |
629 | EXPORT_SYMBOL_GPL(spi_sync); | |
630 | ||
a9948b61 DB |
631 | /* portable code must never pass more than 32 bytes */ |
632 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
633 | |
634 | static u8 *buf; | |
635 | ||
636 | /** | |
637 | * spi_write_then_read - SPI synchronous write followed by read | |
638 | * @spi: device with which data will be exchanged | |
639 | * @txbuf: data to be written (need not be dma-safe) | |
640 | * @n_tx: size of txbuf, in bytes | |
641 | * @rxbuf: buffer into which data will be read | |
642 | * @n_rx: size of rxbuf, in bytes (need not be dma-safe) | |
33e34dc6 | 643 | * Context: can sleep |
8ae12a0d DB |
644 | * |
645 | * This performs a half duplex MicroWire style transaction with the | |
646 | * device, sending txbuf and then reading rxbuf. The return value | |
647 | * is zero for success, else a negative errno status code. | |
b885244e | 648 | * This call may only be used from a context that may sleep. |
8ae12a0d | 649 | * |
0c868461 | 650 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
651 | * portable code should never use this for more than 32 bytes. |
652 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 653 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
654 | */ |
655 | int spi_write_then_read(struct spi_device *spi, | |
656 | const u8 *txbuf, unsigned n_tx, | |
657 | u8 *rxbuf, unsigned n_rx) | |
658 | { | |
068f4070 | 659 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
660 | |
661 | int status; | |
662 | struct spi_message message; | |
f9b90e39 | 663 | struct spi_transfer x; |
8ae12a0d DB |
664 | u8 *local_buf; |
665 | ||
666 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, | |
667 | * (as a pure convenience thing), but we can keep heap costs | |
668 | * out of the hot path ... | |
669 | */ | |
670 | if ((n_tx + n_rx) > SPI_BUFSIZ) | |
671 | return -EINVAL; | |
672 | ||
8275c642 | 673 | spi_message_init(&message); |
f9b90e39 VS |
674 | memset(&x, 0, sizeof x); |
675 | x.len = n_tx + n_rx; | |
676 | spi_message_add_tail(&x, &message); | |
8275c642 | 677 | |
8ae12a0d | 678 | /* ... unless someone else is using the pre-allocated buffer */ |
068f4070 | 679 | if (!mutex_trylock(&lock)) { |
8ae12a0d DB |
680 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
681 | if (!local_buf) | |
682 | return -ENOMEM; | |
683 | } else | |
684 | local_buf = buf; | |
685 | ||
8ae12a0d | 686 | memcpy(local_buf, txbuf, n_tx); |
f9b90e39 VS |
687 | x.tx_buf = local_buf; |
688 | x.rx_buf = local_buf; | |
8ae12a0d DB |
689 | |
690 | /* do the i/o */ | |
8ae12a0d | 691 | status = spi_sync(spi, &message); |
9b938b74 | 692 | if (status == 0) |
f9b90e39 | 693 | memcpy(rxbuf, x.rx_buf + n_tx, n_rx); |
8ae12a0d | 694 | |
f9b90e39 | 695 | if (x.tx_buf == buf) |
068f4070 | 696 | mutex_unlock(&lock); |
8ae12a0d DB |
697 | else |
698 | kfree(local_buf); | |
699 | ||
700 | return status; | |
701 | } | |
702 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
703 | ||
704 | /*-------------------------------------------------------------------------*/ | |
705 | ||
706 | static int __init spi_init(void) | |
707 | { | |
b885244e DB |
708 | int status; |
709 | ||
e94b1766 | 710 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
711 | if (!buf) { |
712 | status = -ENOMEM; | |
713 | goto err0; | |
714 | } | |
715 | ||
716 | status = bus_register(&spi_bus_type); | |
717 | if (status < 0) | |
718 | goto err1; | |
8ae12a0d | 719 | |
b885244e DB |
720 | status = class_register(&spi_master_class); |
721 | if (status < 0) | |
722 | goto err2; | |
8ae12a0d | 723 | return 0; |
b885244e DB |
724 | |
725 | err2: | |
726 | bus_unregister(&spi_bus_type); | |
727 | err1: | |
728 | kfree(buf); | |
729 | buf = NULL; | |
730 | err0: | |
731 | return status; | |
8ae12a0d | 732 | } |
b885244e | 733 | |
8ae12a0d DB |
734 | /* board_info is normally registered in arch_initcall(), |
735 | * but even essential drivers wait till later | |
b885244e DB |
736 | * |
737 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
738 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
739 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 740 | */ |
673c0c00 | 741 | postcore_initcall(spi_init); |
8ae12a0d | 742 |